## Physics (10th Edition)

$1.66\times10^{8}ms^{-1}$
We know: $\frac{n_{A}}{n_{B}}= 1.33$ $\frac{n_{A}}{n_{B}}= \frac{\frac{c}{v_{A}}}{\frac{c}{v_{B}}}= \frac{v_{B}}{v_{A}}$ Thus, we find: 1.33= $\frac{v_{B}}{1.25\times10^{8}m/s}$ Or $v_{B}= 1.33\times 1.25\times10^{8}m/s$ =$1.66\times10^{8}ms^{-1}$. So, the speed of light in material B is $1.66\times10^{8}ms^{-1}$